So just which Orange is the right orange?

The outcome of easyMobile's argument with Orange over the use of the colour could hinge on the quality of a judge's eyesight and will prove a crucial test of European commercial law, experts said yesterday.

The outcome of easyMobile's argument with Orange over the use of the colour could hinge on the quality of a judge's eyesight and will prove a crucial test of European commercial law, experts said yesterday.

Lawyers said the trademark dispute, if it ended up in court, had enormous implications for companies that rely heavily on colour in their branding. The row would come down to whether a court could detect a difference between the two shades of orange at the centre of the dispute.

Stelios Haji-Ioannou, founder of easyJet, on Tuesday announced plans to launch easyMobile using the easyGroup's usual orange livery. The mobile phone company Orange is objecting to the branding, claiming it will cause confusion among consumers and that it has sole rights to use the colour in the mobile phone market.

Orange has registered the colour, officially known as Pantone 151, in the UK for telecoms services and telephones. Stelios uses the shade of orange known as Pantone 021. Stelios is adamant that he has the right to use his corporate colour.

Philip Towler, a partner with patent and trademark lawyers Frank B Dehn & Co, said: "Orange has registered Pantone 151 but it remains to be seen how broadly this protects it against competitors using other shades of orange.

"If Orange and easyGroup end up in court, one issue is likely to be whether the two shades of orange are similar enough to confuse the public. Although the European Court of Justice has laid down general guidelines for deciding whether a likelihood of confusion exists between any two trademarks, it is not clear how they will be applied to this particular kind of situation.

"It is unlikely that Orange will have exclusive use of any shade between red and yellow in the telecoms industry, but ultimately it is up to the courts to decide where to draw the line."

Other companies that have registered colours as trademarks include London Transport, which has registered the red of London buses - Pantone 485 - and the AA, which has the exclusive right to use recovery and repair vehicles painted the yellow Pantone 109 in the UK. The Financial Times once failed to stop London's Evening Standard from printing its business news on pink pages.